Efforts to prevent stroke and to decrease the chance of a recurrent stroke may depend largely upon the control of associated medical conditions such as hypertension, arrhythmia and diabetes. However, the precise roles of various medical conditions, covariates and their interactions in relation to stroke occurrence and recurrence have not, as yet, been determined. The risk factors to be studied are diastolic and systolic blood pressure, diabetes, myocaridal infarction, arrhythmia and transient ischemic attack. Age and sex will be used as covariates. Level of control of risk factors will be measured as ordinal and ratio variables. Construction and use of a model of the likelihood of recurrent stroke which allows for the simultaneous examination of risk factors and their interactions are major goals. The study will follow patients who give informed consent from a large, well-defined catchment area whose initial stroke required hospitalization. Approximately 85-95% of the populkation in the Lehigh Valley, PA-NJ, are hospitalized subsequent to a stroke. Post-stroke follow-up observations, including the level of control of risk factors, will be made three times per year. The expected number of study subjects is between 950 and 1055. The average length of follow-up will be three and one-half years. The study design is longitudinal. Nearly all data will be obtained by direct examination and questioning of patients and knowledgeable relatives or physicians. Existing data will only be used to supplement baseline observations. Study subjects will be ascertained in an ongoing and timely manner through each hospital's stroke team by the study nurse-clinicians. The results of this study will be helpful in determining the mechanisms of stroke, in identifying subgroups of patients at greater risk of recurrent stroke who would most benefit from the effective control of risk factors, and in providing extensive information and tables of risk of recurrent stroke for various risk factor and control level profiles to be used by physicians and patients alike to effect an improvement in levels of control of risk factors.